Hammer EP, are these upgrades worthwhile?

[VmcFlyer]

Well, i've had my Hammer EP for a whole week now and already looking at motor/esc upgrades.

So far i've modified the cooling system to make it much more effecient with a small scoop I fabricated for the rear tube (that really didn't even pick up much water). Now I have a good stream of water out of the outlet even at half throttle. I've also motified the motor can cooling coil by cutting off two coils around the front to allow for the air cooling vents to be clear and took the two cut off coils and mounted on the shaft output side of the motor, jumpered from the rear to the front coils, then vented overboard. Really allows for maximum cooling for a can system. I've ordered some 7cell 3600maH that should come in this week to make the stock motor/esc faster.

Anyone have an idea about the amount of performance change (is it noticable?) in going from 7.2V 6 cell 1500 maH batteries to a 8.4V 7 cell 3600 maH batteries for the stock 550 motor? I've ordered the battery to try but hasn't come in yet, hopefully by the end of the week.

But as with most guys, we can't stop at slightly modified when better alternatives exist. Here is what i'm thinking about going to:

Motor: Graupner 600 Race 8.4
ESC: Proboat Waterproof ESC
Batteries: 3600 maH 8 Cell 8.4V NiMH
Cooling Upgrades: Add (2) Gundert Pickups (one will run to motor brush coolers,one to can cooler)

I'm not looking to race it (no clubs in area) so i'm not wanting to break the bank for a recreational boat, but would like to get it faster just for fun with just a few modifications that won't burn anything up.

Do these modification make sense and will there be a worthwhile increase in the performance?

Thanks all...

[Elroy68]

info lost

[VmcFlyer]

I haven't done anything yet to the boat, the motor, ESC and prop are all stock. All i've done is modify the water cooling system for a better pickup. I'm just looking at future modifications.

I'm not looking for a huge motor, or creating a top notch race boat, its just something I play with on the pond out back for fun. But I wouldn't mind putting a few upgrades to the boat.

Would it be better to just get the 600SP 7.2, stick with 7 cell battery packs, and keep using the stock ESC? If I burn out the ESC i'm not to worried about it as it will just be replaced with a Pro Boat Waterproof one.

I'll still add brush cooling to the new motor and probably run a water line to the stock ESC for cooling. I have a few props laying around the workshop so i'll go and try a few to see what gives the best performance.

Also about the batteries, the battery I ordered is an IB3600 maH 7 cell 8.4V from Offshoreelectrics. I have not recieved it yet so I cannot comment on its color, but what is the warning with the bright green batteries?

[Elroy68]

delete

[VmcFlyer]

I like your idea of the cooling fans, but are you somehow venting to outside air or just recirculating the air inside the hull? Wouldn't it eventually just be circulating hot air and lose effeciency? I'd thought that direct contact brush cooling by water would be more constant and effecient.

As for the water flow. I did tests using an infrared temp gun and it was the reason I changed the cooling system. Prior to the addition of the scoop I was getting motor temps of 155-165 degrees after two consecutive runs on 7.2 1500 maH batteries. The motor wasn't burning hot to the touch, but warmer than I liked. After adding the scoop for increasing the water flow and also opening the air vents on the motor can the average temps after the same runs dropped to 120-130 degrees. Ambient outside air and water temps did not have any major changes between the two tests. This temperature drop could be due to the opening of the air vents also, but i'm happy with the lower temps no matter what causes it.

For the motors, from the data provided on the website the load RPM's were 21,000 for either the 600SP 7.2 and the 600 Race 8.4. But the 8.4 would take a higher voltage and I figured more torque from the 8.4 motor.



Do you think i'd be better off getting the 600SP, 3600 maH 7 cell batteries and leave the ESC stock for now until it quits?

I really appreciate all the input.

[martin richards]

There isn't a quantum leap in performance from a 500 to a 600. But there would be on a 700 on 12 plus cells. Restricting it to 12 you can get by without any water cooling and the 700 has a good reputation for outlasting the smaller motors.
If that's not in your mind, the 600 is much happier on 8 cells than the 500.

[Elroy68]

delete!